The technical advisory group discussed fire protection and shared/common spaces for multiplex housing, with general support for requiring a sprinkler system and questions about how common use areas, shared storage, and dwelling separations should be handled.

Mike (fire official) explained that NFPA 13R focuses on living spaces and that sprinklers reduce other code constraints; he told the group "sprinklers provide trade ups" and that extending 13R coverage into limited common areas is feasible and commonly cost‑neutral because the domestic water service can be upsized rather than adding a separate fire line.

TAG members debated which sprinkler standard should apply. Micah noted a national proposal to expand NFPA 13D allowances in future cycles but emphasized that for this appendix TAG should align with the current 2024 code. Several participants recommended 13R for stacked multiplexes because 13D works better for side‑by‑side townhouses, not stacked flats.

Common amenity spaces (lobbies, mail rooms, limited indoor bike or trash rooms) were discussed. Ardel Jala said Seattle’s middle‑housing interim regulations require bike and trash accommodations but do not require those spaces to be indoors. Members agreed that allowing a limited set of accessory/common uses would increase flexibility, but that code language must specify separations and sprinkler coverage where those uses create additional hazards (for example, stored batteries). Mike noted NFPA 13R section 6.6 as guidance for where sprinklers are required.

Dwelling unit separation: TAG members confirmed a one‑hour separation between units is the baseline in the draft appendix; some members asked whether a two‑hour separation could be an alternative to sprinklers. The group generally preferred sprinklers as the primary life‑safety tool and flagged the two‑hour alternative for later review.

Outcome: The TAG left the sprinkler requirement highlighted for final text edits and asked staff to circulate NFPA guidance and develop draft language describing which limited common uses are allowed, required separations, and the relationship between sprinklers and separations.